Apparatus for eliminating ceramic cores



July 17, 1962 A. POWERS 3,044,087

APPARATUS FOR ELIMINATING CERAMIC CORES Filed Nov. 17, 1959 2 Sheets-Sheet 1 iifigzg gse ALEX POWERS ATTORNEY July 17, 1962 A. POWERS 3,044,087

APPARATUS FOR ELIMINATING CERAMIC CORES 2 Sheets-Sheet 2 Filed Nov. 17, 1959 INVENTOR JJJ.LLLI.LIE.

ALEX POWERS jZM/Zb ATTORNEY Ill] 3l Ihu UH-32 3,044,087 APPARATUS FOR ELIMINATW G CERAh HC CORES Alex Powers, 9498 York Road, North Royalton 33, Ohio Filed Nov. 17, 1959, Ser. No. 853,665 3 Claims. ((31. 153) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to the removing of cores from castings and, more particularly, toan apparatus for removing ceramic cores from investment castings by reciprocating the cores along a wire while immersed in a caustic bath whereby the chemical reaction between the molten caustic bath and the ceramic cores removes the cores from the casting.

It has been the practice in the past to remove ceramic cores from castings by simply immersing the casting with the cores therein into a caustic solution whereby the leaching of the caustic solution would slowly remove the cores from the casting. Since only the core portions near the end of the core are exposed to the caustic solution, it took considerable time to remove cores in this manner and when the reaction products accumulated on the ceramic cores because of the lack of means for carrying them away, the reaction between the solution and the cores would be essentially stopped.

Another method for removing the cores from the cast ing has been to use flexible drills. However, this method has proved to be quite expensive and impractical in cases where a large number of small holes are present in the investment casting.

The present invention overcomes the difiiculty of the reaction products accumulating on the core as the leaching process takes place because a plurality of wires are provided for insertion through the ceramic cores and the castings are reciprocated in a caustic bath relative to the wires whereby the wires act as a means for carrying away the reaction products.

This apparatus for removing the cores also has advantage over the previous apparatus for drilling with small flexible drills in that it is less costly and also it is a more positive apparatus for removing cores. The reciprocal movement of the cores relative to the wires also provides a mechanical abrasion to aid in removing the particles of the ceramic which have accumulated within the casting.

An object of-the invention therefore is to provide an improved device for removing cores from investment castmgs.

A further object of the invention is to provide a device for removing ceramic tubes from investment castings by bringing fresh caustic material in contact with an appreciable area of the core.

A still further object of the invention is to provide a means for removing exhausted caustic ceramic solution from the active ceramic caustic interface in order to speed up the leaching process of a caustic bath and a ceramic core.

A still further object of the invention is to provide a mechanical device for providing abrasion to remove particles of ceramic from the cores of an investment casting.

A further object of the invention is to provide a simple and durable apparatus for effectively removing cores from castings without the use of drills or specifically designed tools.

Further objects and advantages of the present invention will be more readily understood by reference to the fol- States Fatent lowing detailed description when considered in connection with the accompanying drawings wherein: I

FIG. 1 is an elevational view of the complete apparatus of the present invention for removing cores from investment castings.

FIG. 2 is a sectional-end view taken along lines 22 of FIG. 1 and FIG. 3 is an enlarged elevational view, partly in section, of a portion of the apparatus of FIG. 2, showing the investment casting and wires threaded therethrough.

Referring now to FIG. 1, there is shown an apparatus 11 for removing cores from investment castings 18 comprising a stand having a plurality of pipe legs 12 secured to a floor (not shown). The legs 12 are connected by welding or other suitable means to a cross member 13, also of pipe construction.

A pair of V-shaped members 14, as shown in FIG. 2, are secured to the cross member 13 with the legs of the V depending down and away from the cross member 13. The members 14 are inter-connected at their lower ends by a pair of bars 15 by welding or any other suitable means whereby a rigid unitary structure is provided.

A U-shaped hangar comprising rods 16 and bars 28 and 29 is connected to the bars 15 as shown in FIG. 2 with the rods 16 connected to the bars 15 by the insertion of their ends through holes in the bars and thelower portions of the rods 16 are immersed in a molten caustic bath in container 17 which may be of a material such as Mullite, as shown in FIG. 1.

The investment casting 18, in this case a small turbine blade, has a plurality of tube-like ceramic cores inserted therein, as shown in FIG. 3. An actuator rod 19 is secured rigidly at its lower end to the casting 18 by welding or other suitable means and the upper end is bent in a horizontal position and inserted through a hole in the bar 21, as shown in FIGS. 1 and 2.

The middle portion of the bar 21 is rectangular in crosssection; however, the ends of the bar are circular in crosssection and a pair of sliding cams 22 are slidably mounted thereon. A guide member 23 is rigidly connected to each of the legs 12 and a rod head 24 is connected to each end of the bar 21 and provided with an aperture slidably mounted on the guide 23 whereby the movement of the bar 21 is limited to a vertical movement by the guides 23 and rod heads 24.

The means for imparting the vertical movement to the bar 21 and rod 19 is a gear motor 25, chain drive 26 and sprockets 27. The sprockets 27 are rotatably mounted on shafts rigidly connected to the cross member 13 by brackets not shown. The cams 22 are pivotally connected to the sides of the sprockets 27 and as gear motor 25 turns the sprockets 27 in the counter clockwise motion, as shown in FIG. 1, the earns 22 move in a circular direction and impart a vertical movement to the bar 21.

As shown in FIGS. 2 and 3 the rods 16 are rigidly connected at their lower ends by a bar 29 and a similar bar 28 rigidly connects them slightly above their mid-portion. A plurality of stainless steel wires 31 are threaded through the tubular ceramic cores in the casting 18 and are looped around the bars 28 and 29 and a suitable clamping means such as clamp 32, shown in FIG. 3, secures the looped ends.

From the above, it can readily be seen that the device provides a novel means for removing the ceramic cores from the investment casting 18 by the reciprocal movement of the casting 18 along the wires 31 while submerged in the caustic bath within the container 17. Since the wires 31 are stationary and the member 13 is moving relative thereto, the wires will remove any reaction products deposited in the cores due to the chemical reaction between the cores and the caustic bath, While at the same time bringing into contact with the inside of. the ceramic tubes, fresh caustic material. Also, the wires 31 act as a mechanical abrasive means to Wear away the cores as the casting 18 moves relative to the wires 31. Although only one pair of rods 16 and one casting 18 are shown within the drawing, it is to be understood that a plurality of rods 16 and castings 18 could be operated at the same time merely by providing a U-shaped frame member such as the frame formed by the rods 16 and the connecting rods 28 and 29 and an actuator rod 19 for each casting submerged in the caustic material.

Furthermore, applicant has disclosed only one means for imparting the reciprocal movement to the bar 21 and rod 19 in order to move the casting 18 relative to the wires 31; however, it is to be understood that other means could be used to produce this movement without involving the invention as long as casting 13 moves approximately parallel to the wires 31.

- From the foregoing description taken in connection with What is claimed is:

1. In an apparatus for removing ceramic cores from investment castings immersed in a caustic bath the improvement comprising, a first means coaxially disposed within said cores and extending therethrough and a second means for moving said cores and casting relative to said first means whereby the reaction products within said cores are removed.

2. The apparatus, as defined in claim 1, in which said first means comprises a plurality of steel wires threaded through said cores and said second means includes a gear motor operably connected to said castings.

3. A device for removing ceramic cores from an investment casting comprising; a container for a caustic bath, a plurality of spaced apart wires, said wires and said casting adapted to be immersed in said caustic bath in said container, means for mounting said casting adjacent said wires whereby each wire is coaxially threaded within a core and extends therethrough and means for reciprocating said casting relative to said wires whereby fresh caustic solution is brought into contact with said cores.

References Cited in the tile of this patent UNITED STATES PATENTS 2,796,366 Carter June 18, 1957 FOREIGN PATENTS 335,025 Germany Mar. 26, 1921 

